Detail

The AboutDialog offers a simple way to display information about a
program like its logo, name, copyright, website and license. It is also
possible to give credits to the authors, documenters, translators and
artists who have worked on the program. An about dialog is typically opened
when the user selects the About option from the Help menu. All parts of
the dialog are optional.

About dialog often contain links and email addresses. AboutDialog
supports this by offering global hooks, which are called when the user
clicks on a link or email address, see aboutDialogSetEmailHook and
aboutDialogSetUrlHook. Email addresses in the authors, documenters and
artists properties are recognized by looking for <user@host>, URLs are
recognized by looking for http://url, with url extending to the next
space, tab or line break.
Since 2.18 AboutDialog provides default website and email hooks that
use showURI.

Note that Gtk+ sets a default title of _("About %s") on the dialog
window (where %s is replaced by the name of the application, but in order to
ensure proper translation of the title, applications should set the title
property explicitly when constructing a AboutDialog, as shown in the
following example:

The license of the program. This string is displayed in a text view in a
secondary dialog, therefore it is fine to use a long multi-paragraph text.
Note that the text is only wrapped in the text view if the aboutDialogWrapLicense
property is set to True; otherwise the text itself must contain the
intended linebreaks.